analogWriteFrequency() takes one parameter - the carrier frequency to run PWM at.

Both the latter two are shown in an example sketch AnalogWriteFrequencyAndResolution which can be found in the "Analog" section of "Examples" ("Examples" is a dummy library - find it in the list of library examples).

I am using the current release with the Arduino IDE to program a Clicker2 for PIC32MX - this works well with MacOS (with a MacBook Pro) but does not work well with the Linux machine we normally use to programme various boards. The error occurs in the final download to the board once it is ready to load.

Thanks this seems to work! I had (wrongly) assumed that as the USB port had been used for various other boards that it would work for the Clicker 2, but clearly it required a bit more adjustment to the Linux system. Many thanks.

Most USB boards present a virtual serial port, and being in the "dialout" group gives you access to those. However the clicker2 uses a HID bootloader instead, so a device node /dev/ttyACMx isn't created. Since your existing permissions are keyed to the group that node is in, if there isn't one then your existing permissions are no longer used - you need to create a different set of permissions that work in a different way - and that is what udev is now doing for you.

Your existing permissions are still valid for accessing a USB serial port created by your sketch, of course.

I've been using MPIDE 0023 for ages and thought I'd upgrade to the new fancy Arduino 1.6.13 with 1.3.1 chipKIT core. Wooh yeah!
I haven't updated my coding environment in years, but my WinXP laptop is running on it's final prayers now and MPIDE 0023 is no longer supported, and is considered "a threat", in OSX. I have an interesting problem to report. I must say, I'm not sure where exactly the problem is - and bear with me - but:

I've gotten my old code to compile after a few tweaks (still requires disabling DSPI2 and DSPI3 on my MAX32 board def though).
But the problem is that Serial2 doesn't seem to work properly. It does work somewhat, but the communication "stutters", in lack of a better word. I have a Arduino Mega2560 connected to it (on 500 000 baud ) that handles a light matrix on its end, and the lights go haywire. When sending proper data over the interface it does get there, but it's like trying to read a book in darkness while someone flicks the light on and off all the time.

These are facts:
* I've changed from WinXP MPIDE 0023 to Mac OSX 10.10.5 Arduino 1.6.13 + core 1.3.1. (big jump!)
* A simple empty sketch causes Serial2 to "glitch"/"stutter", so it's not my code - it's in the core.
* There has been trouble with DSPI (not used or linked at the moment though) and hardware serials before.
* Serial(0) and Serial3 are confirmed to work reliably with computer serial com and serial com with a wavTrigger. Unsure about Serial1.

I realise this might be stupid questions, but nonetheless important;
1) What has changed when it comes to hardware serials from MPIDE to the new core?
2) Is the core 100% compatible with Arduino 1.6.x, or at least the same functionality as MPIDE 0023?
3) Are custom baud rates unsupported and could this be the problem? (It's a bit of an inconvenient process to update the Mega)
4) Any tricks, tips or things I can try to help verify/resolve this?